By Dr. Kate Scannell, Syndicated columnist
First published in print: 09/21/2014

You can always find me in a crowd -- if you're a mosquito.

I could be concealed within total-body protective gear, adorned with mosquito-repellant bands on my ankles and wrists, lathered with DEET and oil of lemon eucalyptus, topped with a permethrin-infused hat, and, still, if there's a mosquito within flying distance it will hunt me down and bite me. It will release pheromonal signals, inviting all its friends to join the blood fest.

It's not just the ferocious itching from these bites that bothers me. Or my cortisone---slathered ankles making it look as though I'm always wearing white athletic socks. Or being haunted by the nightmarish image of a blood-sucking mosquito that had been magnified to gigantic proportions in a pre-med biology seminar.

In particular, mosquito-borne viral infections have been receiving much attention lately. The buzz is that many have been spreading beyond their traditional geographic confines due to shifts in mosquito habitats instigated by changes in temperature and precipitation associated with global warming. For example, although West Nile Virus was originally isolated in 1937 in Uganda, it wasn't until 1999 that the first documented outbreak occurred in the Western Hemisphere. That outbreak in New York City was convincingly linked to climatic changes, and data now reflect the nearly global geographic distribution of the virus.

In conjunction with warmer temperatures favoring mosquito proliferation, California's current drought is also contributing. That's because birds -- who are the primary carriers of WNV -- are being driven to share increasingly scarce water sources with mosquitos. More mosquitos in greater contact with infected birds leads to more birds becoming infected via the mosquitos biting them. A vicious cycle ensues, making it more likely for mosquitos to acquire WNV -- and, therefore, more likely to transmit it to humans.

Reflecting this trend, the California Department of Public Health reported this month that the proportion of WNV-infected mosquitoes "is at the highest level ever detected" in the state. And as of Sept. 16, it had received reports of 12 deaths and 311 human cases so far this year -- more than double the number last year.

The acceleration in cases is concerning. Though roughly "only" 25 percent of people reportedly develop symptoms after acquiring WNV, many of them will experience persistent or permanent health problems. Furthermore, about half of the symptomatic group will develop neuroinvasive disease -- serious involvement of the spinal cord or brain. In this latter subgroup, mortality rates can approach 10 percent.

As mosquito habitats spread to previously unexposed populations, other mosquito-borne viruses are posing greater public health risks as well. Dengue fever -- a debilitating viral infection once restricted to the tropics -- recently spread to Japan, and its local transmission was documented last year in Florida, New York and Texas. It's estimated that, worldwide, dengue virus now causes about 100 million infections and 12,500 deaths each year.

Also on the move is chikungunya virus -- a name derived from an African word meaning "to become contorted." Known to cause severe joint pains and fevers in humans, this virus was first discovered in Tanzania in 1952. In 2013, it made its debut in the Americas, spreading rapidly in the Caribbean. And by June of this year, health officials in several U.S. states -- including California -- newly reported having residents who tested positive for chikungunya virus after traveling to the Caribbean.

Considering the worrisome expansion of these and other mosquito-borne infections, a report this year in the American Journal of Tropical Medicine and Hygiene recognizes mosquito-borne viruses as "a major public health risk," increasing the importance of ready identification and control of such virus outbreaks.

Regrettably, reliable frameworks to support such conversations and actions do not exist. As a result, we've repeatedly witnessed too many people dying unnecessarily. We rush in late, after the crisis becomes too big to ignore -- and more unwieldy and costly to control. The tragic consequences of such a misguided approach to global health are on current display with Ebola's relentless spread.

Still, there are things we can do on individual and local fronts to promote public health efforts. At the voting booth, we can help elect candidates who understand public health issues and support reliable infrastructures for their timely management.

The urgent need for this cannot be overstated, especially when budget cuts undermine our capacity to address public health problems. For example, underscoring this point, the CDC recently reported that federal funding for WNV surveillance and testing was cut by 61 percent from 2004 to 2012.

Considering the cutbacks on disease reporting and mosquito monitoring, it warned, "the ability to rapidly detect emerging and outbreak-threshold threats and to rapidly initiate prevention measures to minimize human morbidity and mortality ... might be compromised."

We simply cannot view our health in isolation because it is so dependent on our environment. Neglecting public health infrastructures that reflect the reality of our global interconnectedness will only come back to bite us in the end.

YOU SHOULD KNOW
A person can reduce their risk of West Nile Virus infection by:
• Staying indoors at dawn and dusk when mosquitoes are most active.
• Using a repellent containing the active ingredients DEET, Picaridin, oil of lemon eucalyptus, or IR3535 before going outdoors.
• Dumping or draining water that has been standing for more than three days, including neglected swimming pools, birdbaths, pet dishes, tire swings, and flower planters.
These items provide a perfect place for mosquitos to lay their eggs, which increases the risk of being infected with WNV.
• Repairing broken or torn screens on windows and doors to keep mosquitoes from entering your home.Reference: The California Department of Public Health

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